This would actually appeal to me a lot, since it would remove all ambiguity from the relationship between me (the customer), the proprieter, and my use of the t

This would actually appeal to me a lot, since it would remove all ambiguity from the relationship between me (the customer), the proprieter, and my use of the table. I'm always very nervous when I work in a coffee shop, so I'm always looking around to see how long other people staying so I can stay within the norm. This would remove that entirely. Potential enhancement: the staff will babysit your table for you while you go to the bathroom. That would be a big win.